Press unloading devices of the type shown in U.S. Pat. Nos. 2,609,776 and 3,206,040 are used in the mass manufacture of automobiles to load and unload large metal panels in presses. One known device of this type operates at a speed of approximately 19 strokes per minute and is driven by compressed air which acts upwardly on a piston in a single acting vertically arranged cylinder. The rapid expansion of air due to the speed of operation results in a frosting and icing condition at the inlet end of the cylinder which combined with condensation of water in the air creates a problem with respect to the speed of operation of the press unloader.